The present invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36). It relates generally to a noninvasive, nondestructive, and rapid technique for characterizing eggs, and more particularly to the measurement of acoustic resonances in eggs for characterization and quality control.
Currently, the characterization of eggs is performed manually. For example, the identification of fertilized eggs or eggs having double yolks is accomplished by "candling" where a bright light source is placed behind an egg, and the shape of yolk portion determined by a human observer. Additionally, it would be of significant economic value if a technique were available for automated, remote, noninvasive determination of shell thickness, strength, and integrity as an aid to egg packaging. Moreover, egg freshness and contamination are of considerable concern for public health reasons. As an example, the present technique used for determining the presence of Salmonella in eggs involves a yolk culturing process which requires several hours.
In U.S. Pat. No. 5,062,296, entitled "Resonant Ultrasound Spectroscopy," which issued to Albert Migliori on Nov. 5, 1991, the inventor describes the use of resonant ultrasound spectroscopy, and more specifically, resonant response spectra derived from ultrasonic excitation of objects, to characterize objects. Ultrasound characterizes excitation frequencies beyond human hearing, or above 20 kHz. Since such high frequencies are absorbed or severely attenuated by organic materials, especially when liquid systems are involved, the teachings of the Migliori patent are reasonably directed to solid materials.
An elastic thin shell of revolution possesses many modes of vibrations that are commonly referred to as the resonant modes or resonant frequencies. If the shell is mechanically excited at frequencies that coincide with these resonant frequencies, the resulting large amplitude vibrations of the shell body can easily be detected. At other frequencies, that is, away from resonance, the vibrational response of the shell is minimal.
Most experimental acoustical studies to date have relied on artificially made resonators. Eggs represent a class of resonators in which a sturdy, but thin, shell completely surrounds fluid contents. The vibrational modes of an eggshell are modified by the physical properties of the egg white and yoke.
Accordingly, it is an object of the present invention to provide an apparatus and method for noninvasive, nondestructive, and rapid characterization of eggs.
Another object of the invention is to provide an apparatus and method for remote, noninvasive, nondestructive, and rapid characterization of eggs.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.